function [ x_new ] = Matrix_FourPointAvarage_boundary( x1,x2,x3,x4,omega )
% Input:
% x(4,:,:)
% x = [i-1 i i+1 i+2] (the four adjacency matrices)
% omega is the tension parameter
%-----------------------------------------------------------------
% Nir Sharon 26-05-12
%-----------------------------------------------------------------
alpha = (1+14*omega)/(2+8*omega);
x_new = GM2(GM2(x1,x2,alpha),GM2(x3,x4,(-.25)),-4*omega);

end